Hernández, C. (Carmen)

Landa, J. (Jorge)

Navarro, M.R. (María Rosario)

Villamor, B. (Begoña)

English

Repositorio Institucional Digital del IEO

1WKARCM 2015Annual growth pattern and age validation trials of Scomber colias in the Bay of Biscay using otolithsNavarro, M.R., Villamor, B.; Landa, J.; Hernández, C.Instituto Español de Oceanografía (IEO)C.O. Santander Workshop on Age Reading of Chub Mackerel (Scomber colias) [WKARCM]Lisbon (Portugal), 2nd-6th November, 20152WKARCM 2015Backgroundü The age estimation criteria of S. colias are not stillinternationally standardized and have never been validated orcorroborated in Iberian waters.ü This work presents the growth pattern in the Bay of Biscay(Cantabrian Sea, ICES Div. VIIIc) based on samples from aperiod of two years (2011, 2012).ü A semi-direct validation of the age estimation of this species inthe area is performed, at first time, based on the nature of theedge and the otolith marginal increment analyses.ü A verification criterion is also performed, the consistency of theage interpretation is tested by the regularity of the incrementsformation.3WKARCM 2015Material and Methodsü A total of 1991 S. colias collected fromlandings of commercial vessels during2011 and 2012 (Cantabrian Sea, ICESDiv. VIIIc) were sampled.ü In addition, 590 individuals weresampled during the acoustic surveysPELACUS0411 and PELACUS0412,and 29 individuals from the trawlsurveys DEMERSALES2011 andDEMERSALES2012, carried out inApril and September of 2011 and 2012,respectively.ü Total length of all samples wasmeasured to the nearest mm.ü A total of 2185 pair of sagitta otolithswere aged, 1447 of which from the firstsemester and 738 from the second.ü The nature of the edge (hyaline oropaque) was also recorded for all ofthem.-11º -10º -9º -8º -7º -6º -5º -4º -3º -2º -1º42º43º44º45º46º47ºLa Coruña Gijón SantanderIberian PeninsulaBay of BiscayCantabrian SeaSem 1 Sem 2 Total Sem 1 Sem 2 Total2011 461 322 783 245 9 254 10372012 561 387 948 180 20 200 1148TOTAL 1022 709 1731 425 29 454 2185Commerial landings SurveysYEAR TOTAL4WKARCM 2015Material and Methodsü Diameter and radius of 343 otoliths weremeasured, as well as the radius of eachannulus. This otoliths were selected inorder to obtain a good representation ofotoliths by month, sex and fish length.ü The absolute marginal distance (AMD =distance between the end of the lasthyaline annulus and the edge) and thedistance between the last two hyalineannuli (Di,i-1) were also measured in111 of those otoliths, for estimating therelative marginal distance (RMD = ratioof the AMD and Di,i-1) (Panfili 2001).ü All these measurements obtained usinga microscope connected to an imageanalyzer (NIS-Element) and recorded inmicrons (µm).Males Females Indeterm. TOTAL Males Females Indeterm. TOTAL2011 47 62 9 118 11 13 0 242012 115 98 12 225 51 36 0 87TOTAL 162 160 21 343 62 49 0 111Otoliths measured Otoliths with RMDAMDDi,i-1R1R2 RtMeasurement  axis5WKARCM 2015Typical Chub mackerel otoliths in Division VIIIcAge 0177 mmOct. 2012Age 1188 mmApr. 2012Age 2309 mmJan. 2012Age 3363 mmFeb. 20121121236WKARCM 2015Typical Chub mackerel otoliths in Division VIIIcAge 3381mmSept. 2012Age 4388 mmApr. 2012Age 5469 mmJun. 201212312 3 412 3 4 57WKARCM 2015Difficulties:  Checks (false rings)Age 2391 mmAug. 2012Age 3362 mmAug. 2012Age 4390 mmFeb. 201212checkcheck12312 3 4checkü Checks well identified.Otoliths included in thestudy.8WKARCM 2015Difficulties:  ChecksAge 2/3 ??381 mmJun. 2012Age 3 ??355 mmApr. 2012Age 3 ??397 mmApr. 201212312checkcheckcheck123123checkcheckcheckü Doubts when assigningthe age in this kind ofotoliths: NOT used in thisstudy9WKARCM 2015Resultsü The relationship betweenotolith radius and fishlength was significant, andwas expressed as a stronglinear relationship.Otolith radius/Fish length relationship y = 0.0044x + 0.5091R² = 0.8633012340 100 200 300 400 500Otolith radius (mm)Fish length (mm)2011-2012y = 0.0042x + 0.561R² = 0.82230.01.02.03.04.00 100 200 300 400 500Otolith radius (mm)Fish length (mm)2012y = 0.0045x + 0.4599R² = 0.90490.01.02.03.04.00 100 200 300 400 500Otolith radius (mm)Fish length (mm)2011 10WKARCM 2015Resultsü The distribution of each annulus ofS. colias have a normal distribution with adecreasing otolith growth rate with age.ü This linearly decreasing interval betweenincrements is a verification criterion thatforms the basis of age estimation (May,1965).TRENDS IN PATTERS OF GROWTH010203040501.2 1.5 1.8 2.1 2.4FrequencyOtolith radius (mm)2011Age 1Age 2Age 3R1R2R3010203040501.1 1.4 1.7 2 2.3FrequencyOtolith radius (mm)2012Age 1Age 2Age 3Age 4R1R2R3R4010203040501.2 1.5 1.8 2.1 2.4FrequencyOtolith radius (mm)2011-2012Age 1Age 2Age 3Age 4R1R2R3R4Age 1 Age 2 Age 3 Age 42011 34 67 7 12012 5 117 72 142011-2012 39 184 79 1511WKARCM 2015Resultsü The monthly proportion of edge type of S. coliasindicates an annual periodicity in the formation of thehyaline and opaque annuli, appearing the opaqueedge mainly from June to Decemberü The winter (hyaline) annulus seems to be entirelyformed in April.ü RMD also is higher in the second half of the year,between July and December, with higher values inJuly-August 2012 and November 2011. The variabilityof this results can be explained by the low number ofotoliths from which RMD could be measured.Nature of the otolith edge andmarginal increment analyses (RMD)0.000.100.200.300.400.500%20%40%60%80%100%JanFebMarAprMay Jun JulAugSepOctNov DecRMDOtolith edge (%)2011HORMD0.000.100.200.300.400.500%20%40%60%80%100%JanFebMarAprMay Jun JulAugSepOctNov DecRMDOtolith edge (%)2012HORMD0.000.100.200.300.400.500%20%40%60%80%100%JanFebMarAprMay Jun JulAugSepOctNov DecRMDOtolith edge (%)2011-2012HORMDRMDMonth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL2011 11 12 10 36 8 10 22 10 1192012 17 12 29 35 19 17 10 14 14 25 15 19 2262011-2012 28 24 39 71 19 25 10 14 24 47 25 19 34512WKARCM 2015ResultsCatch Length distribution 01000200030004000500060007000800090001000018 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52N ('000)Length (cm)2011Division VIIIcSubdivisión IXa NorthTotal Catch =  22450 t01000200030004000500060007000800090001000018 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52N ('000)Length (cm)2013División VIIIcSubdivisión IXa NorthTotal Catch =  15551 t01000200030004000500060007000800090001000018 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52N ('000)Length (cm)2012Subdivisión IXa NorthDivisión VIIIcNo Length samplingü The commercial catches of chub mackerel in the Bay ofBiscay (ICES div. VIIIc) is formed mainly of big individuals (34-40cm), which correspond to individuals from 2 years or more.ü Younger individuals are presented in the commercial catchesin Galician waters (ICES div. IXaN). Otoliths from this area willbe joined to this study shortly.ü A more completed length distribution of chub mackerel in theBay of Biscay is obtained during the acoustic survey PELACUS,carried out in March-April every year.13WKARCM 2015ResultsCatch at age 2011010020030040050060010152025303540450 1 2 3 4 5 6Weight (g)Length (cm)AgeLength and Weight at  Age- VIIIc 2011L (cm) W (g)020004000600080001000012000140000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15+NumberAgeCatch at age VIIIc-2011ü Chub mackerel present in theBay of Biscay an exponentialgrowth during early years. Thegrowth slow down when theindividuals reach 4 years.14WKARCM 2015ResultsLength frequency distribution  by age in the catch 201105010011 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49Age 1010020011 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49Age 202000400011 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49Age 3010002000300011 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49Age 402000400011 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49Age 50500100011 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49Age 6ü Chub mackerel from the catch of 2011in the Bay of Biscay shows a normaldistribution of the length frequency byage.ü This gives consistency to the ageestimation criteria in which this study isbased.15WKARCM 2015Summary and Conclusionsü The age reading method of chub mackerel otoliths is based on the knowledge of the date of capture and the annual growthpattern of the Chub mackerel otoliths.ü Age equals the number of complete opaque growth zones corresponding to the expected annual growth pattern of the otolithand excluding the marginal edge development of the year (criteria of complete growth zones).ü A linear decreasing interval between increments was observed in this study, this being a verification criterion that forms thebasis of age estimationü Seasonal otolith edge formation: winter (hyaline) annulus predominate from January to April, with a maximum in April, and theopaque annulus predominate from May to December. RMD is also higher in the second half of the year, between July andDecember.ü Typical chub mackerel otoliths from Bay of Biscay present a second annulus with a characteristic wide area.ü Some otoliths present a well marked false ring or check around the middle of the second annulus that is usually well identifiable.ü Others otoliths presents one or more checks well marked, which make more difficult the estimation of their age as can bemistaken with true rings. This is more frequent in otoliths from older individuals.ü The commercial catches of chub mackerel in the Bay of Biscay is formed mainly of big individuals (34-40cm), which correspondto individuals from 2 years or more.ü During early years, chub mackerel individuals growth exponentially. When they reach the age 4 the growth slow down.ü The otolith selection for this study was made in order to obtain a good representation of otoliths by month, sex and length. Futuresteps in this study will include a more completed selection by age in order to include in the analysis individuals older than age 4.A good representation of otoliths by age also will allow a study of the AMD to observe the differences in the edge formation byage. Also, a next step in this study will be the addition of the analysis of the chub mackerel otoliths from Galician waters (ICESdiv. IXaN).

Annual growth pattern and age validation trials of Scomber colias in the Bay of Biscay using otoliths

Navarro, María Rosario

Villamor, Begoña

Landa, Jorge

Hernández, Carmen

Digital.CSIC

http://www.repositorio.ieo.es/e-ieo/bitstream/10508/10188/1/Navarro%20et%20al%202015_Colias%20Validation%20WKARCM.pdf

Annual growth pattern and age validation trials of Scomber colias in the Bay of Biscay using otoliths

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